Hybrid devices wherein biologically derived components interact with non-biological components offer the opportunity, as yet largely unexploited, to bring the forces of evolution and natural selection to bear on problems of engineering. Recently, attempts to marry biology and engineering to create various biohybrid constructs have been steadily increasing. A limited number of novel biohybrid sensor applications have already been reported, and in some cases commercialized, that incorporate “smart” molecular-scale biological components. These have attracted considerable interest from both the biomedical and biotechnology communities worldwide. However, little has been done to date in developing integrated nanodevices and systems such as microanalytical systems incorporating novel, engineered nanobioconstructs and their analogues for use in integrated nanodevices and systems such as bio-optical hybrid sensors capable of very sensitive and selective nanoscale detection due to enhanced performance characteristics as determined by a prescribed biohybrid Figure of Merit (FoM). Potential applications include microsystem applications requiring low-level light detection capability (e.g. micro total analytical systems (μTAS) for immunoassay, genomics and proteomics), such as “point-of-care” diagnostic medicine, biotechnology, space bioengineering, energy harvesting and conversion, and countermeasures to biowarfare for defense, among others.
In general, the current state of the art for engineering design as taught by Koen (Koen, 1987) and many others (Otto and Wood, 2001), has not led to the achievement of device components, stand-alone devices, nor engineered systems that function or otherwise perform at a prescribed FoM and oftentimes typically perform at levels significantly below optimal FoM levels and theoretically achievable maximum FoM limits.
The well-known area of thermoelectric device design exemplifies the present ability of engineering design heuristics to achieve a desirable thermoelectric FoM (i.e., ZT) that significantly exceeds current ZT device values of ˜1 although a ZT value of 4 is theoretically possible (Rowe, D. M., 1995). The present inability of those skilled in the art to achieve desired material and device FoMs characterizes virtually all engineering device design applications spanning diverse disciplinary fields and broad industry product segments.
In recent years, less effective and predictive empirical approaches have been used to devise novel hybrid devices that incorporate naturally derived biological materials and constructs, or mimetics thereof, that have resulted in enhanced device performance relative to their non-hybrid engineered counterpart. To date, however, the engineering method does not teach how to design, select, modify or otherwise alter smart, nanoscale energy-interactive materials, such as molecular-scale biophotonic components, derived from natural or biomimetic analog constructs, despite their intrinsically superior and potentially adaptable structural and performance characteristics. Nor does the engineering method show those skilled in this art how such nanoscale materials can be further embodied or employed as components, or as stand-alone devices, that are capable of producing robust and scalable energy-interactive biohybrid devices and systems that function at a desired FoM not yet achievable by conventional engineering means.
Photoactive semiconductors such as Si photovoltaic cells (as one example of a large scale device) have long been known. They have been employed in various devices and applications for years. Their varying responsivity to certain light wavelengths throughout the visible spectrum has been observed as well. On the biological side, thermophilic photosynthetic bacteria such as Chloroflexus aurantiacus (C. aurantiacus) and other species have been studied and reported upon. The photosensitive “light antenna” embodied in the chlorosomes of C. aurantiacus and in various other components of other organisms, have been studied and reported upon, as well. Perhaps as a result of inconsistency of results with photosynthetic bacteria, these organisms and their chlorosomes or other photosensitive components have not been incorporated into practicable devices. A need exists for improvement of the performance of photoactive devices throughout the light spectrum, and for techniques for harnessing the photosensitivity of photosynthetic bacteria in photoactive devices. More fundamentally, there is a need to identify inconsistencies in the photosensitivity (or other photonic or electroactivity) of biological specimens and to apply a method or methods to ameliorate or eliminate such inconsistencies and/or to optimize the performance of biological components for particular applications.
As one means of gathering knowledge about a system, Design of Experiment (DOE) analysis is a widely used statistical modeling approach, reported in detail elsewhere (Montgomery, 1991). A unique advantage of DOE, particularly as applied to complex adaptive systems, is its ability to elucidate not only the effect of the controlling variables, but also their complex interactions. Use of DOE analysis with biological or hybrid biological/non-biological devices and systems has not been encountered. In particular use of the powerful DOE approach in connection with forced adaptation in biological systems (such as bacteria) to move the systems toward a more consistent (i.e. dependable) performance and/or otherwise optimize the performance of biological components in biohybrid devices is not known. Figure of Merit (FoM) is another concept often used in engineering (among other fields such as economics, chemistry, astronomy, etc.). FoM is a measure of a device's performance. It is used in many contexts. However FoM as a design-driving measure, particularly with respect to adaptive biological organisms-based systems, devices and components is considered to be a radical departure from other uses of this concept. Further, as applied to biological organisms, parts thereof or systems made up of such organisms, control of multiple environmental variables is needed if the DOE approach is to be applied. The transfer function of a device, circuit or system is another engineering concept that is well understood. However, that concept has not ordinarily been applied to biological systems, if at all. A need exists to apply engineering concepts like DOE, FoM and the transfer function to the analysis, evaluation and design of biological, bioengineered and hybrid systems, components and devices.